Grafts, for example hemodialysis grafts, are often used for patients who need to receive frequent injections, blood filtration, or vascular access procedures. For example, patients who receive kidney dialysis typically received several treatments per week. In order for the patient to receive treatment, the patient's skin must be punctured with a hemodialysis needle. Such needles are typically about 15-17 gauge, and they leave a puncture which takes some time to heal. With the frequency of dialysis treatments, puncture wounds accumulate, and there is a danger of undermining the patient's veins.
It has become common to implant a graft in the patient's arm to receive the punctures. Typically, the graft is a tubular member which is implanted in the patient's forearm, although other locations may be used. The graft is connected between two spaced points in the circulatory system. In the past, veins from animals were used as the graft material, but today it is common to use an artificial material, such as polymer tubing. However, the punctures in such tubing tend to leak under the pressure of the circulatory system. In all cases, the graft can not be used immediately and must be allowed to heal-in or mature, before it can be punctured. Efforts have been made to use tubes made of a self-sealing polymer or to provide a multilayered structure to resolve these problems; but such grafts have not been proven to be a reliable solution to long term patency.
It would therefore be desirable to provide a graft made of an artificial material which can reliably prevent blood leakage from repeated punctures when in use. Preferably, it should be relatively simple in construction, made of medically accepted and biologically compatible materials, and its implantation and use should be no more complicated than the existing grafts.